What is the difference between a patrician and a plebian

Generally, the patricians were the rich class in ancient Rome and the plebians were the middle/poor class. They rarely mixed socially, though on occasion a plebian would marry a patrician. Prior to the formation of the Republic, that was against the law.

Patricians had more power, and they created laws to keep plebians down. Plebians had less power, and they were always trying to rise.